Discrimination of chiral amines by dimethyldiketopyridino-18-crown-6 (1) is studied by free energy perturbation (FEP) and molecular dynamics (MD) methods. 1 has two (S)-chiral centers and discriminates chiral amines through host-guest interactions. The optically active amines in this study are α(1-naphthyl)ethylamine, methylbenzylamine, cyclohexylethylamine, and sec-butylamine. The trends in binding free energy differences obtained from FEP calculations were in excellent agreement with experimental results obtained in the gas phase. In order to explain the enantioselectivity of the host in terms of the host-guest interactions at the molecular level, we analyzed the structures generated by 10-ns MD simulations of host-guest complexes. The suggested chiral discrimination mechanism, the π-π interaction and the steric repulsion between the guest and the host, was verified by our MD simulation analysis.
|Number of pages||18|
|Publication status||Published - 1 Dec 2000|
- Chiral separation
- Free Energy Perturbation (FEP)
- Gas phase
- Molecular Dynamics (MD)
ASJC Scopus subject areas